#include<stdio.h>
#include<string.h>
int main()
{
    char arr[501] = { 0 };
    gets(arr);
    int len = strlen(arr);
    int sum = 0;
    int i = 0;
    int flag = 1;
    for (i = 0; i < len; i++)
    {
        int j = 0;
        flag = 1;
        for (j = i - 1; j >= 0; j--)
        {
            if (arr[i] == arr[j] || (arr[i] > 127))
            {
                flag = 0;
                break;
            }
        }
        if (flag == 1)
            sum++;
    }
    printf("%d\n", sum);
    return 0;
}